Bonding machine with oscillator keying control



Sept. 2, 1952 E. B. sNYDER BONDING MACHINE WITH OSCILLATOR KEY'ING CONTROL 2 SHEETS-SHEET l Filed April 6. 1949 www: ur-"cn 777 @M Sept 2, 1952, E. B. SNYDER 2,609,480

BONDING MACHI-NE WITH OSCILLATOR KEYING CONTROL Filed April 6. 1949 2 SHEETS-SHEET 2 19 L 5i" "Q5/(im 46 attoweq/ Patented Siep-t. 2, 19502 BONDING MACHINE WITH OSCILLATIOR KEYING CONTROL Ellsworth Bush Snyder, Somerville, N. J., assignor to The Singer Manufacturing Company, Elizabeth, N. J., a. corporation of New Jersey Application April 6, 1949, Serial No. 85,776

8 Claims.

This invention relates to switching mechanism for keying the oscillator of an electronic bonding machine. More particularly, it relates to a switching mechanism in which the time relation between the switch operations and the electrode position may be adjusted so that the switch must be opened before the bonding electrode can begin its lift.

This general type of oscillator control is well illustrated by the U. S. application of Hacklander et al., Serial No. 47,356, filed September 2, 1948, to which application reference may be made for a more complete understanding of the invention. It has been determined that, in order to prevent al1 detrimental sparking, it is necessary that the electrode be in engagement with the material to be bonded whenever the oscillator is turned on and off. While the mechanism of the aforesaid patent application Serial No. 47,356 is, in general, satisfactory in this respect, there are conditions under which sparking may occur, and it is to prevent this that the improved mechanism of this invention has been developed.

The prior 4mechanism referred to is so constructed that the reciprocatory electrode must start to lift before the switch can operate to turn off the oscillator. After bonding, the material at the seam line is neither as thick nor as resilient as it was before bonding, and, for this reason, the electrode does not have to rise much vertically before it is completely out of the material. Thus it may happen, particularly in the case of thin material, that the electrode emerges from the material before the oscillator has been turned off, in which case undesirable arcing and burning may occur.

It is, therefore, a primary object of this invention to provide a switch mechanism for a bonding machine of the reciprocatory electrode type, including mechanism for interlocking the action of switch and electrode whereby the switch must be opened before the electrode can begin its lift. f

It is a further object of this invention to provide adjustable elements for an oscillator switch mechanism for use with a bonding machine employing a reciprocatory electrode, whereby the timing between the switch operation and the contact of the material with the electrode may be precisely adjusted to gain the maximum bonding time for each electrode reciprocation.

In the present embodiment of the invention, these objects are attained by interposing a pivoted fork between the lift eccentric and the lifting stud of the electrode bar, the fork embracing the lifting stud in such a manner as to provide a lost motion connection therebetween. An adjustable switch contact is carried by the fork which, due to the lost motion, must move upwards before lifting the electrode bar. This upward movement of the Work opens the switch contact and turns oif the oscillator before it can lift the electrode.

With the above and other objects in view, as will hereinafter appear, the invention comprises the devices, combinations and arrangements of parts hereinafter set forth and illustrated in the accompanying drawings of a preferred embodiment of the invention, from which the several features of the invention and the advantages attained thereby will be readily understood by those skilled in the art.

In the drawings:

Fig. lis a longitudinal section taken through a portion of a bonding machine embodying the invention.

Fig. 2 is a front end elevation, partly in section, of the machine of Fig. 1 with the cover plate removed.

Fig. 3 is a horizontal section of the bracketarm head and taken on the line 3-3 of Fig. 2.

Fig. 4 is a section, partly in elevation, taken on the line 4--4 of Fig. 3.

Referring to Fig. 1, I represents an overhanging bracket-arm of a bonding machine of the general type shown and described in the above mentioned U. S. application Serial No. 47,356 to which reference maybe had for a detailed description of the parts not fully disclosed herein. A bed 2 carries the overhanging arm I which terminates in a hollow head 3. Journaled in a bearing 4 in the bracket-arm I is an arm shaft 5 to which is imparted a rotary motion by means clearly set forth in the vaforesaid application. A second shaft 6 is journaled beneath the bed 2 in bushing bearings 'I and 8 and to this shaft is imparted an intermittent rotary motion in one direction by means also set forth in the aforesaid application. A feed wheel 9 is secured to the shaft 6 and extends through a suitable slot in a plate I0 carried by the bed 2.

Secured to a reduced terminal portion II of the arm shaft 5 by means of a set screw I2 is a hub I3 carrying an eccentric pin I4 on which is 'mounted the inner race ring I5 of a ball bearing. The outer race ring I6 serves as a lifting cam surface as will be presently set forth.

' A fork member I1 formed with a throat portion I8..is pivoted in the head 3 by means of a pivot screw I9. 'A tension spring 22, secured at end of the electrode-bar is a split collar 28 sei cured thereto by screws 23, and .formed with a stud portion 3u. A roller 3| is secured to said stud 3c by means of a pivot screw 32, said vroller being positioned to loosely engagevthethroalzpori tion I8 and to form therewith a lostmotion C Qnthe lower electrode 64 to load-end tuning elements E8 and 69 which, in turn, are connected to a radio-frequency oscillator through terminal 'I0 in the same manner as shown and described in application Serial No. 47,356.

Operation It will be understood that rotation of the armshaft 5 imparts a rising and falling motion to the ele ctrode-.bar.23` through the agency of the eccentric-pin M, bearing ring l, fork Il, roller 3| and spring 2t. However, the falling motion of Vithe electrode-bar .is arrested when the stop pin neet-ion. Threaded into and dependingiromthe split collar 28 is a stop-pin 33 "Whichmaybe adjustably secured thereto by means of a-lock nut 3d. A presser bar 36, carrying a roller presser 3l, is journaled in a vverticalloearng 38 .Xed-i-n the head`3. A lea'f ,spring'exertspressure upon the upper end of the presserjbar 3.6. to Vbias 'itin a downward direction. Anpextension bar Atil is secured to the .upper endof the presser' bar lby tightening a split, portion L4`| "thereof around said presser bar .by taking .up on a .screw "42.

To the upper end of the extension'bar v4l! ,is secured a switch plated?. by means of screws .154.

The switch plate 43,is made .ofinsulation material and .carries a switch contact 45 secured theretol'byY means ofgrivelts "48. 'The switch contact .165 is formed as a' 'leaf spring' of. ,electrically conducting material andv has 'its lfree end V bent 'to form a transverse tubular portion 35. AV pin41 is secured to the switchplate t3 Vand lis'ben't. to enter the tubular portion of the leaf springwand provides a stop to limit the upward 1 movement of the contact.

The .fork memberk is 'iorme'dwithaboss .portion 43 which carries an insulated switch plate ed secured thereto by -means of screws 50 threaded into the boss portion. .An adjustable switchcontact is made of electrically conductingmaterial and .is secured to one side. of the switch plate @El by means discrewsiz .and;53. The switch contact! is'iormed witha portion `Ellnbent over to present a contactingsurfaceliSfor engagement with the tubular portion iottheilower contactA i5 when the forkmember moves to* follow the cam surface provided'by `the .outer .race ring A notch't formed inthe upper surface ofthe switch plate t9, as .seen best 4inlA Fig.` 31 provides a seatfor a hair-pin spring 57;,the mainbody of which is recessed in thehead 3 and embraces `one of the serews employed to secure acover plate 'et to the head. 'The springl. providesra downward biasing force .for the y.Switcl'i contact 5| which minimizes the `tendency tobounce, at contact impact.

Conductors and Si connect the switch contacts A and 5| respectively, to aradio-,frequency oscillator to provide cathodekeying' therefor, precisely as shown..and described .inthe aforementioned appl-ication.SerialfNo 47,356v vto which reference may be 4made for Ithespeclicoscillator and electrode conne'dtions.

Anupper electrodeff is threaded vupon the lower terminal portion of the electrod'efbarZB and is securedinproper.position relative to the direction of iced by `rneansof aset .screwj6 3.

A lowerstationary electrode y541ssecured to an insulation block' 65 vcarried by abracketf' .which is secured tothe be'd2. .A conductor'fl connects :33 engages th'etop-surface 'Il of the extension bar All.

andiinal-ly the surface 55 of Contact 5| engages 'The `fork l?! continues to move downward the tubular portion 35 of contact d5, thus closing Tthe oscillator keying circuit and bonding begins with the electrodo 62 fully seated in the material l2. The fork will continue to drop until all theyieldin the contacts -45 and 5| has bn ,taken up, at which time the roller 3| Ywill be spaced from the lower limbof the fork Il by a certainclearance distance. .After the outer race ring tengages the `fork for the lifting movement, ,the fork must move upwardsby a distance equal to the aforesaid clearance distance before theiorkengages the roller 3| to lift the electrede-bar` 23. Duringthis movement of the fork, the contacts d5 and-5| -are separated to` open the oscillator keying circuit and stopthe bonding-before the electrode v-62 begins to lift away from the material 7.2.

Thus, by the interposition of a lost-motionffork between the lift eccentric-and the electrode-bar and by employing `the work motion to operate the .switch contacts, theoperation of said switch may be restricted to occur only when the electrode 'E2 is seated linthematerial 72. This is the desired condition for no sparking.

It .will be seen that the maximum penetration of the .electrode .G2 into the material 1.2 may be controlledby adjusting the stop `pin 33 .relative to the surf-ace 'H of the extension Vbar te. Furtherfor anygiven adjustment of the pin 33, the percent penetration tends to be constant regardless of thickness because (l) the surface 'H responds to changesin the material thickness sensed by the roller presses Bland transmitted through the presser-bert, and (2) the yield of the material is substantially proportionalto Athe thickness.

It is, of course essential that the time during which the oscillator is lturned on be the maximum possible for each reciprocation of the electrode 62. Thus, it becomes important to. close the switch contacts 45 and5| as soon as possible after the electrode is Vfully seated in the material112. `To accomplish this, the contacttl is made adjustable .relative tothe plate 49 by providing aslotlfor thescrew 53 so that `the contact Yl may be rotated about the screw '52v and locked in position by means of the screw 53. Thus, the machine may be setto `the position in which the electrode BZhas just reached vits maximum penetration in the material, and, while in this'position, the contact 5| may be adjusted as described so as to just fail to engage the contact 45. yThis insures the desirable results that (l) the switch operations, both opening and closing, will occur always `with the electrode in the material, and (2) the time for bonding will beY arnaximum consistent with the desirable conditions of (1K) Having thus set forth the nature of the invention, what I claim herein is:

1. In an electronic seaming machine having a reciprocatory electrode electrically connected to a radio-frequency oscillator, and a movable presser cooperating with a feed mechanism for advancing material past the electrode, a lift eccentric, a fork operated by said lift eccentric, a switch operated by said fork for turning on and off said oscillator, an electrode-bar carrying said electrode, and a lost-motion connection between said fork and said electrode-bar, for moving the fork to take up the lost motion and open the lswitch before the electrode can begin its lift.

2. An electronic seaming machine comprising a frame, a shaft mounted for rotation in said frame, a lift eccentric carried by said shaft, a fork pivoted in said frame and biased to engage said eccentric for operation therewith, an electrode-bar carried by said frame for vertical reciprocation, a lifting stud connected to said electrode-bar and loosely embraced by said fork to provide a lost motion connection therewith, a

first electrical contact mounted on said fork, a presser-bar, a second electrical contact mounted on said presser bar and cooperating with said rst electrical contact to form a switch which opens and closes periodically responsive VKto the rotation of said shaft.

3. In a machine for seaming material by the application thereto of a radio-frequency electric field, a frame, a shaft mounted for rotation in said frame, a lift eccentric carried by said shaft, an electrode-bar mounted for vertical reciprocation in said frame, a spring for biasing said electrode downwardly, a lifting stud secured to said electrode-bar, a fork pivoted to said frame and loosely embracing said lifting stud to provide a lost motion connection therewith, said fork being operatively connected to said lift eccentric, a presser and a feed wheel for feeding the material past the electrode, and a switch comprising a resilient contact carried by said presser and a cooperating contact carried by said fork.

4. In a machine for seaming dielectric material by the application thereto of a radio-frequency electric field, a frame, a shaft mounted for rotation in said frame, a lift eccentric carried by said shaft, an electrode-bar mounted for vertical reciprocation in said frame, a spring for urging said electrode-bar downwardly, a lifting stud secured to said electrode-bar, a fork pivoted to said frame and formed with a throat portion which loosely engages said lifting stud and forms therewith a lost-motion connection, means for urging said fork into driving connection with said lift eccentric, a presser in continuous contact with the material, and a switch comprising a rst contact mounted on said fork, a second contact mounted on said presser and cooperating with said first contact to open and close a circuit for controlling said electric field.

5. In a machine for seaming dielectric material by the application thereto of a radio-frequency field, means for progressively feeding said material through said eld, a reciprocatory electrode for periodically engaging said material, a

stop to limit the material-engaging movement of said electrode, an oscillator, switch contacts for turning on and off said oscillator, a pivoted element carrying one of said contacts, means for directly actuating said element to periodically close and open said contacts, and a lost-motion link connecting said electrode with said contactcarrying element whereby said electrode is actuated after the lost motion has been taken up by said link.

6. In a machine for seaming dielectric material by the application thereto of a radio-frequency field, an electrode, an oscillator electrically connected to said electrode to establish said field, a switch mechanism for turning on and off said oscillator, means for operating said switch mechanism periodically, link means providing a lost-motion connection between said switch-operating means and said electrode for imparting to said electrode a reciprocatory motion into and out of said dielectric material in timed relation Vwith the turning on and turning off of said oscillator, and stop means for limiting the travel of said electrode into the work, said stop means cooperating with said lost-m-otion link to provide continued movement of said switch mechanism after the electrode has come to a stop in the material 7. In a machine for seaming dielectric material by the application thereto of a radio-frequency field, a reciprccatory electrode, an oscillator electrically connected to said electrode to establish said field, switch contacts for turning on and off said oscillator, pivoted fork means connected directly t-o one of said switch contacts and, through a lost-motion connection, to said electrode, stop means for arresting the movement of said electrode, and means for operating said fork means for moving said one of said switch contacts to engage the other switch contact to turn on said oscillator after the electrode comes to rest against said stop means.

8. In a machine for seaming dielectric material, a reciprocatory electrode, a source of energy connected to said electrode, switch contacts for turning on and off said source of energy, pivoted fork means connected directly to one of said switch contacts and, through a lost motion connection, to said electrode, stop means for arresting the movement of said electrode, and means for operating said forli means for moving said one of said switch contacts to engage the other switch contact to turn on said source of 4energy after the electrode comes to rest against said stop means.

ELLSWORTH BUSH SNYDER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

